1. Field of the Invention
The present invention relates to a solid-state image pickup element, in particular, a mounting method and structure for the solid-state image pickup element in the image reading-out apparatus for reading out an optical image by use of the above-mentioned solid-state image pickup element, wherein the above element is employed as the image reading-out portion in the facsimile device, copying machine, scanner, etc.
The invention further relates to a supporting structure for supporting an adjusted member such as the solid-state image pickup apparatus, etc.
2. Description of the Prior Arts
In a conventional optical image reading-out apparatus by use of the solid-state image pickup element, as shown in FIG. 19, an object 3 is focused on a solid-state image pickup element, through an image focusing lens 2 and the same is read out therefrom.
Furthermore, the solid-state image pickup element employs a one-line solid-state image pickup element 4 having plural miniature optoelectric conversion elements arranged in a row (hereinafter, called solely "pixel") usually consisting of a dimension of several .mu.m .times. several .mu.m.
In such an image reading-out apparatus, the line image focused by an image focusing lens 2 is situated on a solid-state image pickup element 1. And further, in order to read out the optical property (focus, magnification, etc.) with the predetermined precision required, it is necessary to perform positional adjustment by finely moving the image focusing lens 2 and the pixel line 4 of the one-line solid-state image pickup element 1 in the five directions of x, y, z, .beta., and .gamma. as shown in FIG. 20. The reference numeral 26 represents an optical axis, in FIG. 20.
Furthermore, in recent years, in order to read out the color image, a solid-state image pickup element 1a having three-line elements 4a, 4b, and 4c respectively arranged on three lines per respective pixels; Red (called "R", later), Green (called "G", later), Blue (called "B", later) respectively having the peaks of the light separation into its spectral components sensitivity at R, G, and B is employed on some occasions.
On this occasion, since a margin for the position of the three-line solid-state image pickup element 1a occurs also in the direction .alpha. shown in FIG. 20 in addition to the adjustment in the above-mentioned five directions, it is necessary to perform the adjustment in six directions in total (a first axial direction along the optical axis 26, second and third axial directions which are perpendicular to the first axial direction; and first, second and third rotational directions respectively around the first, second and third axial directions).
Usually, the high precision (.+-. several .mu.m) of the positional adjustment of such solid-state image pickup element 1a is required on this occasion. In particular, the indispensable one for attaining the above-mentioned requirement is the technology of preventing the position of the solid-state image pickup element 1a from deviating from the predetermined position at the time of fixing the element after adjusting the position thereof as mentioned above.
Even though the position is adjusted with high precision, when the position deviates at the time of fixing it turns out to be necessary to adjust the position once again. Or otherwise, in the case of adopting the fixing method capable of separating, there is no way except for abolishing the separated portion, and thereby there arises a cause of taking longer time for adjusting the position or raising the manufacturing cost. In such a situation, the technology as mentioned above is required.
As to such fixing, although the fixing method by screw has been frequently adopted conventionally, the other fixing method by adhesive agent has been tried in recent years on many occasions, because the amount of the positional deviation is too large (several hundreds .mu.m or several tens .mu.m) and on the other hand the positional deviation caused by the latter method is smaller than that caused by the former method.
As to the mixing method by use of the adhesive agent, the method is roughly classified into two. The first one is the method of bringing both portions to be bonded into direct contact with each other. The second one is the method of providing a gap therebetween. The former method is called "Direct Contact Adhering", while the latter is called "Filling-up Adhering".
In recent years, there are proposed various sorts of solid-state image pickup element fixing methods. As one example of them, the specification of Japanese Laid-open Patent Publication No. 62-139466/1987 describes that a complicated mechanism is disposed at the side of the image reading-out apparatus such that the portions to be bonded are always brought into direct contact with each other even though the position of the solid-state image pickup element is adjusted.
In such a method as described in the specification, the positional adjustment itself of the solid-state image pickup element not only turns out to be complicated, but it is necessary to provide position adjusting mechanism not required for attaining the essential function of reading out the image in the image reading-out apparatus. Consequently, the considerable cost of the parts not required for attaining the essential function is added inevitably, and thereby it follows that the cost of manufacturing is raised largely.
Furthermore, since there exist a large number of movable parts in the adjustment mechanism, many portions to be bonded have to be provided necessarily, and further positional deviation due to bonding occurs on many occasions. Those above-mentioned matters are the defects of the conventional structures (prior arts).
Furthermore, in the case of adopting the method proposed in Japanese Laid-open Patent Publication No. 62-268263, although the directly contacting portion for fixing the solid-state image pickup element by use of an adhesive agent is not formed with a complicated mechanism and thereby the cost is not raised, the solid-state image pickup element is brought into direct contact with a part of the image reading-out apparatus and adhered thereon, and there is no problem if the directly-contacting parts of the above both portions are located on the predetermined position, and on the contrary, if the directly-contacting parts thereof deviate from the predetermined position it is impossible to determine the solid-state image pickup element's position only by bringing both into direct contact. Consequently, a washer is interposed therebetween for adjustment of positioning and thereafter both are bonded to each other.
However, in such a method, it is difficult to perform the positional adjustment of several-.mu.m level rapidly and with high precision. Furthermore, it is necessary to prepare the washer per each adjustment and thereby it turns out to be difficult to cope with the problems for the mass-production thereof.
Furthermore, the porn, at issue (problem to be solved) commonly proposed in the above-mentioned two Japanese Laid-open Patent Applications is that since both portions to be bonded are brought into direct contact with each other and nevertheless both are not brought into completely tight contact with each other and thereby there exists therebetween a gap of several hundred .mu.m or less, the adhesive agent infiltrates into (fills) the interior of the member to be fixed by the action of the capillary phenomenon on some occasions in relation to the factors; the surface tension and density both inherent in the adhesive agent or the afore-mentioned gap.
For this reason, according to the willing state thereof, it causes a positional deviation of the member to be fixed at the time of hardening the adhesive agent. Furthermore, in the case of employing an optically-hardening type adhesive agent, the light rays cannot be radiated into the interior of the member to be fixed, and thereby not-hardened portions remain in the adhesive agent. In such a situation, even though the members to be fixed are put on the predetermined position, the hardening of the adhesive agent advances later due to the thermal variation, etc., and thereby the positional deviation occurs. The above is the defect of the related (prior) art.
On the other hand, there are proposed various sorts of the fixing method of the solid-state image pickup element utilizing the filling adhesion. One of them is described in Japanese Laid-open Patent Publication No. 61-118707/1986 proposing the fixing method. In this method, there is provided a complicated mechanism enabling the positional adjustment of the solid-state image pickup element having a fixing-side member and a directly-contacting portion. In such construction, the directly-contacting portions are not brought into direct contact with each other. Instead, the adhesive agent fills the portions having the gap not coming into direct contact with each other.
In such a method as mentioned above, it is not profitable that cost up may be caused as in the afore-mentioned case of Japanese Laid-open Patent Publication No. 62-139466/1987. Furthermore, there exist another direct-contact portions of the solid-state image pickup element and the fixed-side member in addition to the portions to be bonded. In particular, since screw and resilient body are employed as the direct-contact member, the screw is loosened due to vibration and/or temperature (thermal) variation, or the resilient body exerts an eternal force on the solid-state image pickup element by the action of vibration or plastic deformation. Those matters cause the positional deviation of the solid-state image pickup element on some occasions.
Usually, in the method of "Filling Adhesion", in case that the adhesive strength and the positional deviation due to adhesion are respectively required to be set to the desired values without any unevenness, it is necessary to uniformly fill the portions to be bonded with the adhesive agent so as to form an optional shape, and it is further necessary to set the amount of the adhesive agent as small as possible.
In this method, in order to uniformly fill the portions to be bonded with the adhesive agent, it is preferable to employ the adhesive agent having low viscosity. However, as shown in FIG. 22, if a gap E between mounting plate 38 and solid state image pickup element 1 is not small, the adhesive agent 24 flows out from the gap E in the case of employing the adhesive agent of low viscosity.
On the other hand, even though the gap E is made small, the adhesive agent 24 flows out from the gap portion by the action of the capillary phenomenon on some occasions. In the case of employing an optically-hardening type adhesive agent, the light rays are not radiated on the gap portion and thereby the not-hardened portion remains. Even though the portions to be bonded are located on the predetermined positions at the time of adjusting and fixing, the hardening of the adhesive agent proceeds later due to the temperature (thermal) variation. Probably, it follows that the position of the solid-state image pickup element deviates from the predetermined.
Furthermore, in this method, there exists a problem to be solved that the required amount of the adhesive agent is too much, from the viewpoint of the dimension (square measure) of the adhesive agent coming into contact with the object to be bonded. Consequently, there occurs a troublesome matter that, for the above reasons, the position of the solid-state image pickup element deviates from the predetermined and the cost regarding the adhesive agent is raised. Those are the troubles (demerit) of the conventional (prior) art.
And further, on the other hand, according to the fixing method of the solid-state image pickup element proposed in a magazine; Nikkei Mechanical (published on Jun. 29, 1992-Page 88), there exists no adjustment mechanism for adjusting the position of the solid-state image pickup element.
Consequently, it does not cause any cost-up as mentioned in Japanese Laid-open Patent Publication No. 62-139466/1987, and further, since the object to be bonded is constructed with a cylindrical hole and a cylindrical pin, it does not require a large amount of the adhesion agent, and nevertheless sufficient adhering dimension (square measure) can be secured. It follows that the adhesive strength is improved and the amount of the positional deviation is reduced.
However, even in this method, there arises a problem that the adhesive agent overflows downward if the gap between the cylindrical hole and the cylindrical pin is not small. On the contrary, if the gap is made too small, there arises another problem that it is difficult to put the adhesive agent throughout into the gap. Furthermore, in the case of employing the optically-hardening type adhesive agent, the light rays cannot easily infiltrate into the bottom portion of the gap. Consequently, it needs a long time to completely harden the adhesive agent or not-hardened portion remains. It follows that there arises a problem that the positional deviation of the solid-state image pickup element occurs as in the other method as mentioned above.
In such a situation, the present applicant (inventor) proposes the following structure in connection with the mounting method and the mounting structure of the solid-state image pickup element in the image reading-out apparatus. The patent application describing the above-mentioned method and structure has been filed at the same time as that of the above patent application.
Namely, a mounting structure of a solid-state image pickup element in an image reading-out apparatus proposed by the inventor comprises a solid-state image pickup element, an image focusing lens for focusing image, a fixing member for fixing the solid-state image pickup element which further fixes the image focusing lens, a basic board having the solid-state image pickup element mounted thereon, and a support member for supporting the solid-state image pickup element on which the basic board is mounted so as to be detachable therefrom,
wherein connecting portions are provided between the solid-state image pickup element fixing member and the solid-state image pickup element supporting member, PA1 wherein the connecting portions are bonded to the solid-state image pickup element fixing member after adjusting the position of the solid-state image pickup element supporting member, PA1 wherein the connecting portions are constructed with a projection/hole portion provided on image pickup element and a hole/projection portion provided on the support member for supporting the solid-state image pickup element, PA1 wherein a gap portion between a projection part and a hole part of the projection/hole portion and the hole/projection portion is formed such that the injection side for injecting adhesive agent or the tip end side of the projection part turns out to be wide, and PA1 wherein said connecting portions are bonded to each other by dispensing (painting or applying) the adhesive agent on the gap portion after performing the positional adjustment by use of a jig.
Furthermore, the present applicant (inventor) has proposed the mounting method and the mounting structure of the solid-state image pickup element in the image reading-out apparatus described in Japanese Patent Application No. 6-91733/1994, in which the solid-state image pickup element can be assembled with high accuracy and further the positional deviation seldom occurs thereafter.